Microbial strains are specific variations of microorganisms, such as bacteria, fungi, or viruses, that have distinct genetic, biochemical, or physiological characteristics. These strains can differ in their ability to cause disease, produce certain substances, or survive in various environments. Understanding these differences is crucial for fields like medicine, agriculture, and biotechnology. Researchers often study microbial strains to develop new treatments, improve crop yields, or create biofuels. For example, certain bacterial strains are used in probiotics to promote gut health, while others may be engineered for bioremediation to clean up environmental pollutants.